Tolerability and pharmacokinetics of two formulations of megestrol acetate under fed conditions in healthy volunteers

Abstract

Purpose: Megestrol acetate oral suspension is an appetite stimulant indicated for cachexia. It is available in a conventional formulation and as a nanocrystal dispersion. The aim of this study was to compare the tolerability and pharmacokinetics of these formulations under fed conditions in healthy Korean volunteers.

Methods: This was a randomized, single-dose, 3-treatment, 3-period, 6-sequence, crossover study in healthy Korean volunteers. In each period, participants received single oral doses of conventional formulation 800 mg/20 mL (reference), nanocrystal dispersion 650 mg/5.2 mL (test 1), and nanocrystal dispersion 675 mg/5.4 mL (test 2) after a high-calorie, high-fat meal. The periods were separated by a washout period of 14 days. Serial blood samples were collected up to 120 hours after dosing. The plasma concentrations of megestrol acetate were determined with a validated LC-MS/MS method. Pharmacokinetic parameters were obtained by noncompartmental analysis. Tolerability was assessed by physical examinations, vital signs, clinical laboratory test results, and electrocardiograms.

Findings: Thirty-eight healthy volunteers completed the study. The geometric mean ratios of the AUC(last) and C(max) for test 1/reference were 0.88 (90% CI, 0.84-0.92) and 1.07 (90% CI, 0.99-1.15), respectively. The geometric mean ratios of the AUC(last) and C(max) for test 2/reference were 0.88 (90% CI, 0.84-0.93) and1.03 (90% CI, 0.96-1.10), respectively. All formulations were well tolerated.

Implications: The pharmacokinetic characteristics and tolerability of the 2 megestrol acetate formulations are similar in fed volunteers and suggest no relevant difference in tolerability. ClinicalTrials.gov identifier: NCT01342055.

Keywords: healthy; megestrol acetate; nanocrystal dispersion; pharmacokinetics.